Although cryotherapy as a treatment for severe ROP has been proven significantly effective in preserving vision among children who were born prematurely with birth weights below 1251 grams, there is reason to expect mounting complications over the years in eyes that had severe ROP, whether treated or untreated. As follow-up has continued into school age, eyes damaged by ROP are developing new or more extensive retinal detachment, cataracts, and band keratopathy-all conditions that not only can worsen already poor vision, but also can cause ocular pain. As these children enter adolescence, there is particular concern that eyes with preserved vision will sustain late retinal detachments or progressive photoreceptor failure, and consequent decline of visual acuity. This ongoing study affords the opportunity to ascertain whether the benefits of cryotherapy that accrued during early childhood will be sustained in adolescence. To determine this, an examination will be conducted at age 15 that will include objective masked assessment of both structure and function in treated and untreated eyes with severe ROP. An incidence comparison will be made between treated and untreated eyes for many sequelae and complications, such as late retinal detachment, macular degeneration, and vision failure.